Oral Presentation

The HI gas and radial profiles in semi-analytic models

Author(s): Jian Fu (SHAO)

Presenter: Jian Fu (Shanghai Astronomical Observatory, Chinese Academy of Sciences)

We update the radially-resolved semi-analytic models of galaxy formation based on ΛCDM cosmology simulation, which include both atomic and molecular gas phase in ISM. Our model can reproduce varies of properties of HI gas in nearby galaxies, e.g. the HI mass function, the HI-to-star ratio vs stellar mass and stellar surface density, HI mass-size relation and universal HI radial surface density profile in outer disks. Based on our model results, we can give some physical origins of the observational findings for HI radial profiles. The HI mass-size relation is mainly caused by the conversion between atomic and molecular gas. The universal HI radial profile in outer disks is from the combination of inside-out disk formation and exponential gas accretion. On the other hand, our work on higher resolution simulation can also give more detailed predictions for future nearby HI survey in dwarf galaxies (e.g SKA & FAST).